Upgraded my compressor, now what?

[Licher]

I picked up a 4HP 30gal Campbell Hausfeld horizontal compressor today that puts out 9.4CFM at 90psi. I saw it fill up until it hit pressure and it didn't leak. I think I got a decent deal on it and it seems like it's in good shape but I have some questions and am wondering what I should do.

It's going to stay in my garage which is small, so for now, being semi portable is a requirement. I'll be running a 220 outlet shortly and can handle this part without issue. I'm mainly going to be using it to power my 1/2" impact gun, air ratchet and grinder. I'll probably use it once a month maybe?

One question is what preventative maintenance should I perform to keep it running? I know change the oil, but what else? belt? petcock? anything? Also, if I'm using it once a month, should I drain it completely in between use?

Another question is, I see these inline things that a lot of people have that look like some sort of gauge or filter. What are these, what are the benefits, and do I need one?

I haven't really had a chance to look at the compressor, but I'm not really fond of how the hose is attached with hose clamps. I would like to replace the hose [and clamps] with something that is threaded. How I can I do this? Also, I plan on getting new hoses to accomplish this, so what hose do I get? I see there are two types, pvc and rubber. Is one better than the other? With my previous compressor I believe i bought the 25' rubber hose from harbor freight. It this ok? Is there a difference in quality between brands?

Any help you can provide will be greatly appreciated. I look forward to learning more about compressors.
Here are some photos of the compressor.

 

[jagleaso]

I have the same questions as the OP. Any help guys?

 

[RivennHewn]

Change oil, drain tank, replace fittings and hoses, add in-line filter and oiler, chrome 22's with spinners, flame job.

Done.

 

[skruft]

The hose should be attached with either a proper threaded fitting or a quick-connect device. New hoses usually come with the right threaded fitting.

Change the oil.

At one time this compressor would have had a guard so that you don't catch your hand in the pulley or belt when it's running. This can cause serious injury. At least keep kids away and don't leave it switched on.

You don't have to drain the tank entirely (though I would, if I used mine that rarely) but every now and then you should open the petcock on the bottom to let water out.

 

[strutaeng]

I have a similar compressor, except mine is a 30 gal and had a cheaper quality aluminum pump. The problem with these is the pressure switch/ regulator tend to fail and there are no replacements from the manufacturer. When mine failed I took it to compressor shop and the guy said it was more economical to buy a new compressor!

I went to Grainger and bought a Square D pressure switch and check valve and it worked for another year or so. Unfortunately, my pump was worn out so I swapped the pump and motor and made a larger-capacity machine.

Look at getting/making a belt guard if you have kids around, put a quick disconnect on the regulator and have fun!